Generate Ethereum Private key, Public key, and Address using Bash and OpenSSL

keys

# Generate the private and public keys
openssl ecparam -name secp256k1 -genkey -noout | openssl ec -text -noout > key

# Extract the public key and remove the EC prefix 0x04
cat key | grep pub -A 5 | tail -n +2 | tr -d '\n[:space:]:' | sed 's/^04//' > pub

# Extract the private key and remove the leading zero byte
cat key | grep priv -A 3 | tail -n +2 | tr -d '\n[:space:]:' | sed 's/^00//' > priv

# Generate the hash and take the address part
cat pub | keccak-256sum -x -l | tr -d ' -' | tail -c 41 > address

# (Optional) import the private key to geth
geth account import priv

How to get keccak-256sum command in mac os?

@ciscolxh https://github.com/maandree/sha3sum

on OSX, you can do brew install sha3sum to get the keccak-256sum command.

How to convert from existing key to publicKey.pem. The pem format.

How to format public key to "secp256 compressed form - 66 characters" form?

@Cheny-chen not sure how to do it with OpenSSL; here's an example using Node:

const KeyEncoder = require('key-encoder').default
const keyEncoder = new KeyEncoder('secp256k1')

const pubKey = Buffer.from('04997d9778d772bee04e01522c00d7d52371bd1a27cd87f6cf6f9c828d3a6d0d0da661b58f035aef01db4d7ad1c837ac28f3dec50f54bd351d090db6cb85069cc7', 'hex')

const pem = keyEncoder.encodePublic(pubKey.toString('hex'), 'raw' ,'pem').toString()
console.log(pem)
/*
-----BEGIN PUBLIC KEY-----
MFYwEAYHKoZIzj0CAQYFK4EEAAoDQgAEmX2XeNdyvuBOAVIsANfVI3G9GifNh/bP
b5yCjTptDQ2mYbWPA1rvAdtNetHIN6wo897FD1S9NR0JDbbLhQacxw==
-----END PUBLIC KEY-----
*/

const raw = keyEncoder.encodePublic(pem, 'pem' ,'raw').toString('hex')
console.log(raw)
// 04997d9778d772bee04e01522c00d7d52371bd1a27cd87f6cf6f9c828d3a6d0d0da661b58f035aef01db4d7ad1c837ac28f3dec50f54bd351d090db6cb85069cc7

The letters in public address in this script is all lower cased. Can you make it right? (I know lower case key still works)